Adds functions to Underscore/Lo-Dash for manipulating database-like objects.
It adds:
get
insert
update
updateWhere
remove
removeWhere
save
load
createId
Data can be persisted using the filesystem or localStorage.
Tip You can extend LowDB with underscore-db.
Node
$ npm install underscore underscore-db
var _ = require('underscore');
var _db = require('underscore-db');
_.mixin(_db);
Browser
$ bower install underscore underscore-db
<script src="underscore.js" type="text/javascript"></script>
<script src="underscore-db.js" type="text/javascript"></script>
To use underscore-db with Lo-Dash, just replace underscore
with lodash
Create an empty database object
var db = {
posts: []
}
Create a post
var newPost = _.insert(db.posts, {title: 'foo'});
Display database console.log(db)
{
posts: [
{title: "foo", id: "5ca959c4-b5ab-4336-aa65-8a197b6dd9cb"}
]
}
Retrieve post using underscore-db get
or underscore find
method
var post = _.get(db.posts, newPost.id);
var post = _.find(db.posts, function(post) {
return post.title === 'foo'
});
Persist
_.save(db);
The following database object is used in API examples.
var db = {
posts: [
{id: 1, body: 'one', published: false},
{id: 2, body: 'two', published: true}
],
comments: [
{id: 1, body: 'foo', postId: 1},
{id: 2, body: 'bar', postId: 2}
]
}
get(collection, id)
Finds and returns document by id or undefined.
var post = _.get(db.posts, 1);
insert(collection, document)
Adds document to collection, sets an id and returns created document.
var post = _.insert(db.posts, {body: 'New post'});
If the document has already an id, it will be used to insert or replace.
_.insert(db.posts, {id: 1, body: 'New post'});
_.insert(db.posts, {id: 1, title: 'New title'});
_.get(db.posts, 1) // {id: 1, title: 'New title'}
update(collection, id, attrs)
Finds document by id, copies properties to it and returns updated document or undefined.
var post = _.update(db.posts, 1, {body: 'Updated body'});
updateWhere(collection, whereAttrs, attrs)
Finds documents using _.where
, updates documents and returns updated documents or an empty array.
// Publish all unpublished posts
var posts = _.updateWhere(db.posts, {published: false}, {published: true});
remove(collection, id)
Removes document from collection and returns it or undefined.
var comment = _.remove(db.comments, 1);
removeWhere(collection, whereAttrs)
Removes documents from collection using _.where
and returns removed documents or an empty array.
var comments = _.removeWhere(db.comments, {postId: 1});
save(db, [destination])
Persists database using localStorage or filesystem. If no destination is specified it will save to db
or ./db.json
.
_.save(db);
_.save(db, '/some/path/db.json');
load([source])
Loads database from localStorage or filesystem. If no source is specified it will load from db
or ./db.json
.
var db = _.load();
var db = _.load('/some/path/db.json');
id
Overwrite it if you want to use another id property.
_.id = '_id';
createId(collectionName, doc)
Called by underscore-db when a document is inserted. Overwrite it if you want to change id generation algorithm.
_.createId = function(collectionName, doc) {
return collectionName + '-' + doc.name + '-' + _.random(1, 9999);
}
Everything you need for querying is present in Underscore and Lo-Dash: where
, find
, map
, reduce
, filter
, reject
, sortBy
, groupBy
, countBy
, ...
See http://underscorejs.org/ or http://lodash.com/docs.
Example:
// Using Underscore
var topFivePosts = _(db.posts)
.chain()
.where({published: true})
.sortBy(function(post) {
return post.views;
})
.first(5)
.value();
// Using Lo-Dash
var topFivePosts = _(db.posts)
.where({published: true})
.sortBy('views')
.first(5)
.value();
With Lo-Dash, you can create optimal builds and include just what you need.
Minimal build for underscore-db to work (~2kb min gzipped):
$ npm install -g lodash-cli
$ lodash underscore include=find,where,clone,indexOf
For more build options, see http://lodash.com/custom-builds.
See details changes for each version in the release notes.
underscore-db is released under the MIT License.